Updates to the User Guide for Echo mode. This is still work in progress!

doc/CMakeLists.txt

@@ -72,7 +72,7 @@ set (UG_IMGS
   images/config-menu.png
   images/decode-menu.png
   images/download_samples.png
-  images/echo_144.png
+  images/Echo_1296.png
   images/EME_Deep_0.png
   images/EME_Deep_1.png
   images/EME_Deep_2.png

doc/user_guide/en/vhf-features.adoc

@@ -280,37 +280,29 @@ being readable by anyone listening in.
 
 === Echo Mode
 
-*Echo* mode allows you to make sensitive measurements of your own
+*Echo* mode provides tools for two types of measurements: echoes of
-lunar echoes even when they are too weak to be heard. Select *Echo*
+your transmitted signal from the Moon, and broadband noise power
-from the *Mode* menu, aim your antenna at the moon, pick a clear
+received from the Sun, Moon, and possibly other sources including
-frequency, and toggle click *Tx Enable*. _WSJT-X_ will then cycle
+nearby ground.  In each case the system noise temperature (noise power
-through the following loop every 6 seconds:
+referred to the antenna terminals, expressed in Kelvin degrees) serves
+as the reference noise level.  Such measurements are widely used for
+optimizing a station's capabilities for Earth-Moon-Earth (EME)
+communication.
 
-1. Transmit a 1500 Hz fixed tone for 2.3 s
+For lunar echoes, _WSJT_ generates short fixed-frequency transmissions
-2. Wait about 0.2 s for start of the return echo
+that alternate with reception intervals at the appropriate
-3. Record the received signal for 2.3 s
+Doppler-shifted frequency.  With *Split Operation* set to *Rig* or
-4. Analyze, average, and display the results
+*Fake It* on the *Settings | Radio* tab, check *Doppler tracking* and
-5. Repeat from step 1
+*Own Echo* on the Astronomical Data window.  Point your antenna at the
+Moon and click *Enable Tx* on the main window to start a sequence of
+echo measurements.  Each cycle takes 6 seconds.  If strong enough,
+echoes will be visible in the waterfall.  Their average spectrum will
+be displayed in the Echo Graph window, and numerical parameters in the
+main window.
 
-To make a sequence of echo tests:
+image::Echo_1296.png[align="center",alt="Echo 144 MHz"]
 
-- Select *Echo* from the *Mode* menu.
+... more to come ...
-
-- Check *Doppler tracking* and *Constant frequency on the Moon* on the
-Astronomical Data window.
-
-- Be sure that your rig control has been set up for _Split Operation_,
-using either *Rig* or *Fake It* on the *Settings | Radio* tab.
-
-- Click *Enable Tx* on the main window to start a sequence of 6-second
-cycles.
-
-- _WSJT-X_ calculates and compensates for Doppler shift automatically.
-As shown in the screen shot below, when proper Doppler corrections
-have been applied your return echo should always appear at the center
-of the plot area on the Echo Graph window.
-
-image::echo_144.png[align="center",alt="Echo 144 MHz"]
 
 === Tips for EME